More than two decades after their son was killed by Hamas in Israel, an American couple will file suit Friday in their relentless effort to crush groups that fund terror.

But the chairman and founder of American Muslims for Palestine (AMP), the target of the litigation, denies the group has anything to do with terrorism and calls the claim "Islamophobia."

David Boim was a 17-year-old yeshiva student when he was fatally shot at a West Bank bus stop in May 1996. Four years later, the family sued a group of U.S.-based Palestinian charities linked to Hamas, claiming they could be held responsible for Boim's death under federal anti-terror laws.

In 2004, Stanley and Joyce Boim won a $156 million judgment that ultimately was upheld by a federal appeals court in 2008.

The organizations had argued that they didn't support the military wing of Hamas, that they simply funded aid groups operating in the West Bank. But the court ruling affirmed the principle that those who fund terror groups are responsible under U.S. law for the actions of those groups — even if the donors contend they only intended to support humanitarian activities.

Joyce Boim says the court battles are more about justice than money.

“We think about and mourn our son David every day," Boim, who lives in Jerusalem, said in an email Thursday. "We brought the original suit to prevent other American families from suffering similar tragedies. We pray that this new effort will give more force to the law that seeks justice for terror victims."

"We said 'If you support those groups, you support the military wing,'" Stephen Landes, a lawyer for the Boims, tells USA TODAY. He called the court ruling a "landmark decision" for the Anti-Terrorism Act of 1992, which gave U.S. civil courts jurisdiction when Americans are harmed by international terrorism.

Landes says the couple collected pennies on the dollar from the groups but was satisfied they forced them to shut down.

"Their motivation was not to get rich," Landes said. "They just don't want another penny to go to the types of organizations that killed their son."

Landes says the groups claimed they couldn't afford to pay the judgment and closed up shop. Landes says AMP and its fiscal sponsor, Americans for Justice in Palestine Educational Foundation, are "alter egos" of the defunct groups and should be held liable for the unpaid judgment. He also claims that three AMP officials were once members of the previously sued Hamas-linked charities.

"They moved down the street and put a new name on the door," he says. "If you can change your name to avoid paying a judgment, it makes a farce of the statute."

AMP, founded in 2006, says on its website that it was founded by Americans to educate the American public and media about issues related to Palestine and its heritage. AMP Chairman Hatem Bazian says his group has no connection to Hamas and does no work outside the U.S.

"We are here to educate, to inform and to engage the American public and lawmakers on why the policy in Palestine should consider the Palestinian perspective," he told USA TODAY. "This lawsuit is frivolous and highly Islamophobic."

Boim died after two men drove up to his bus stop and started shooting. Boim was hit in the head; other students with him were wounded. One of the shooters died in September 1997 during a suicide attack in Jerusalem that killed five people and injured 192. In February 1998, the other man confessed to murdering Boim, and a Palestinian Authority court sentenced him to 10 years of hard labor.

The U.S. appeals court that signed off on the judgment noted that Hamas, in addition to terrorist activities, provides health, educational and other social welfare services to Palestinians.

"But if you give money to an organization that you know to be engaged in terrorism, the fact that you earmark it for the organization’s non-terrorist activities does not get you off the liability hook," the court found.